In recent years, computing machines have been in widespread use with increasing opportunities for even those who are not well informed about computing machines (i.e. computing machine beginners) to use computing machines. Such a computing machine beginner occasionally fails to solve a problem arising with a computing machine trouble and carry out periodical maintenance such as deletion of unnecessary files by himself or herself. Therefore, it is necessary to ask someone who is knowledgeable about a computing machine to carry out maintenance. In such an occasion, moving costs need to be covered to send a person who carries out maintenance (i.e. maintainer) to a place where a troubled computing machine is located and carry out maintenance for the computing machine, so that it has been in demand to realize maintenance from somewhere remote.
Meanwhile, in the inside of a computing machine, since various kinds of user data such as photos, addresses, contact information, passwords, business related data, unpublished data and other personal information are stored, requirements that data as stated above must not be seen by a third party and/or leaked need to be satisfied.
As a technique related to computing machine maintenance, JP2004-171412A (patent literature 1) discloses a virtual PC (Personal Computer) rental device, a program for a computer to execute and a virtual PC rental system. According to this related technique, in a thin client of an image transfer type, a VM (Visual Machine) on a server side is rolled back to a normal state, whereby maintenance is carried out. However, since a server administrator who carries out maintenance can freely access data held by the VM, it may lead to the browsing of user data and the leakage of user data.
JP2007-201969A (patent literature 2) also discloses a remote maintenance system. According to this related technique, a computing machine which carries out maintenance is provided with a communication control section and a communication control section demands a person who carries out maintenance to provide a password. By setting the period of validity for the password, it is made possible to specify a period of time to allow maintenance. For this reason, a person who requests a maintenance service can grasp a period of time during which maintenance is carried out, and a feeling of suspicion can therefore be reduced. However, since a person who carries out a maintenance service can, after inputting a password, freely access data, it may lead to the browsing of user data and the leakage of user data.
As stated above, in the above related techniques, since entire data including user data is given to a maintainer at the time of a maintenance work, there is a possibility that user data is leaked. In addition, since a maintainer also carries out maintenance by accessing a user computing machine and operating the user computing machine, there is another possibility that a setting may be changed so that someone other than a user can access entire data including user data.